Among these high melting point and/or hydrophobic compounds, the phytosterols are compounds which have a solid scientific record making it possible to confirm their blood cholesterol-lowering effect. Two types of phytosterols are available on the market: the sterols and stanols (hydrogenated sterols). These sterols or stanols are often offered by different suppliers in esterified form.
These compounds are incorporated in fatty foods such as margarines. Real difficulties exist in incorporating them into very aqueous products such as yogurts and dairy products in general.
The document EP 1 059 851 describes a means of incorporating phytosterols preferably in the form of powder. This powder form is offered less and less by suppliers of sterols in favour of oily forms. It is therefore of prime importance to find another effective means of incorporating phytosterols in this oily form into products with a high water content.
The International Application WO 01/32029 describes a composition comprising a vegetable oil or fat and one or more phytosterols or phytostanols in which the phytosterols and/or phytostanols, which are not in the form of esters, are essentially completely dissolved. The method used consists of heating the phytosterols and/or phytostanols to form a molten mass which is then added to a heated oil or to a heated fat, and the composition thus formed is then cooled down. As regards the possible uses mentioned in this application the preparation of a dairy-based beverage is described, comprising a stage of mixing xanthan gum, skimmed milk powder and skimmed milk, left at ambient temperature to rehydrate the milk powder. Then the mixture is subjected to stirring in order to obtain a uniform dispersion. An oil containing phytosterols is heated to 80° C. and added to the mixture during stirring, then the mixture is subjected to homogenization and UHT treatment. The addition of the oil containing phytosterols heated to 80° C. to the mixture which seems to be at ambient temperature leads to the recrystallization of the sterol which prevents the preparation of a dairy-based beverage or a yogurt.
The U.S. Pat. No. 6,190,270 describes a preparation method for a food ingredient comprising the following stages: heating of one or more sterols to their melting point, combination of the product obtained with one or more emulsifiers in order to produce a homogeneous mixture and cooling down of the mixture under stirring, in order to produce a food ingredient. In this document the use of an emulsifier is always provided.
The document EP 1 212 945 relates to a dairy-based beverage comprising a stanol ester at a rate of 0.2 to 2% by weight which can contain a thickener, among other ingredients. All the applications cited mention the use of stabilizers, essentially thickeners and sometimes emulsifiers.